A non-contact type semiconductor utilizing wireless communication has been started to be used in various uses. The non-contact type semiconductor internally holds various types of information, receives a request externally through the wireless communication, and executes processing according to a request. A typical non-contact type semiconductor can be, for example, the one called “wireless tag (RFID (Radio Frequency Identification) tag and IC tag)”.
Wireless tags are tried to be attached to various articles, animals, plants, etc. The applicable scope of the wireless tag is not limited to areas such as improvement of efficiency of production and distribution, and various applied services that are available after the goods are delivered to consumers are contemplated.
The applicable scope of the wireless tag can include, for example, administration of prices, sell-by dates, etc., and administration of foods stored in refrigerators and best-before dates of foods in a supermarket by attaching the wireless tag to each of the goods therein; authentication at a train ticket wicket by attaching the wireless tag to each season ticket; and payment of tolls on a toll highway (ETC: Electronic Toll Collection).
Not only the cases where the wireless tag is attached to each of goods itself but also various services provided by applying a wireless tag attached to an apparatus such as a mobile phone are contemplated.
The wireless tag is applied to process control, parts inventory control, and product inventory control in a plant by attaching the wireless tag to each of parts handled therein; distribution control and inventory control that trace the distribution process and the inventory status by attaching the wireless tag to each of goods; library holdings management and lending/returning control in a library; etc.
Information recorded in a wireless tag can be read by an apparatus called “reader/writer” and this apparatus can write new information and change recorded information.
Therefore, though the wireless tag has an advantage that information is easily exchanged, a new threat to security, especially, a sense of threat to consumers for privacy invasion is getting strong.
Privacy invasion problems may be arisen that, for example, goods information of goods (for example, the prices of clothes that a person wears) is read in a store other than the supermarket where the person bought the goods and direct mail is sent to the person from an unknown store as to related goods based on the read information, that information on what a person threw away can be easily known to other persons when the person threw away items with wireless tags attached thereto in a dump, and that personal information such as the name of a person registered in a wireless tag that is attached to a members card is read. When personal information is read in a place that a person does not want other people to know that he/she has visited there, the case can be arisen that the information may be used for a malicious purpose such as blackmailing or sending reminders.
To solve the above problems, the technique in Patent Document 1 proposes an IC tag that can convert the encryption scheme of recorded data when necessary, an encryption scheme converting apparatus that transmits an encryption scheme conversion instruction to the IC tag, and a decrypting apparatus that decrypts information from the IC tag. Thereby, the IC tag can disclose necessary information to specific persons. However, the IC tag can keep confidentiality of the information against those other than the specific persons.    Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-302710